President Barack Obama today signaled an aggressive tact for his early re-election campaign, critiquing his Republican opponents by name and insisting he's ready to "fight with every fiber of my being" for a second term.

"How much do you want it?" ABC News' Diane Sawyer asked Obama during an exclusive interview in Las Vegas.

"Badly," the president said, "because I think the country needs it."

"Whoever wins the Republican primary is going to be a standard bearer for a vision of the country that I don't think reflects who we are," Obama said.

"I'm going to fight as hard as I can with every fiber of my being to make sure that we continue on a path that I think will restore the American dream," he said.

Obama pushed back against what he called Republicans' "rhetorical flourishes," including Newt Gingrich's oft-repeated contention that Obama is the "food stamp president."

"First of all, I don't put people on food stamps," Obama said. "People become eligible for food stamps. Second of all, the initial expansion of food-stamp eligibility happened under my Republican predecessor, not under me. No. 3, when you have a disastrous economic crash that results in 8 million people losing their jobs, more people are going to need more support from government."

"The larger point is this: that there's going to be a debate over the next eight, nine, 10 months about how to move the country forward," he said. "They've got an argument. They will make it forcefully. I think it's an argument that is wrong."

Asked whether he believes there's an undercurrent of racial tension in the "food stamp president" criticism, Obama wouldn't say. But he said the rhetoric from conservatives like that used by Gingrich illustrates an attempt by Republicans to engage in the same divisiveness that they profess to decry.

"The American people are going to make a judgment about who's trying to bring the country together and who's dividing it, who reflects the core values that helped create this country … and who is tapping into some of our worst instincts," he said.

Obama also used his first network interview since his State of the Union Address to single out three of his Republican rivals, jabbing Mitt Romney, Newt Gingrich and Rick Santorum as adherents of a failed political philosophy.

"We've got a test of Mr. Romney or Mr. Gingrich or Mr. Santorum's theories. We tried it for 10 years. And it resulted in a huge crash that lost us the most jobs since the 1930s," Obama said of a push for less financial regulation and lower taxes. "And why we would want to adopt something that we just tried and did not work, doesn't make sense."

Obama said the alternative he's offering – higher taxes on the wealthy, particularly millionaires and billionaires, to bankroll new government spending -- is a "a recipe for a fair, sound approach to deficit reduction and rebuilding this country," which he outlined in his speech to Congress and the nation Tuesday night.

"I think whether it's Romney or Gingrich or Santorum or any of these folks, the question to ask them is we now have the lowest tax rates in 50 years. We've seen the highest increase in income for the very top echelons since the 1920s. And if, in fact, we're going to reduce our deficit while still investing in those things that we know make America grow, somebody's got to pay for it," he said.

"I think better I pay for it or Mr. Romney pay for it or Mr. Gingrich help pay for it than a senior citizen suddenly seeing several thousands of dollars in additional Medicare increases or a student who's trying to struggle their way through school," he added.